Sanding block



Patented May 7, 1940 v UNITED STATES PATENT OFFICE SANDING BLOCK Carl W. Rechel, Sacramento, Calii. Application August 10, 1939, Serial No. 289,342

1Clam. (c1. 51187) This invention relates to hand tools for gripping or holding abrasive-coated sheets used in polishing or surfacing work.

It is an object of the invehtion to provide a sanding block particularly adapted to the finishing of the painted surfaces of automobiles or the 1ik.

Another object of the invention is to provide a sanding block which will produce an abraded surface that is perfectly smooth and free of undercuts.

The invention possesses other objects and features of advantage, some of which, together with the foregoing, will be specifically set forth in the detailed description hereunto annexed. It is to be understood that the invention is not to be limited to the specific form thereof herein shown and described as various other embodiments may be employed within the scope of the appended claim.

Referring to the drawing:

Figure 1 is a top plan view of the sanding block of my invention.

Figure 2 is a longitudinal vertical sectional view of the sanding block. The plane in which the view is taken is indioated by the line 2-2 of Figure 1.

Figure 3 is an end elevational ing block.

Figure 4 is a view showing the action of a sheet of abrasive paper held inthe sanding block of my invention.

Figure 5 is a fragmental vertical seotional view showing a modified form of my invention.

In the refinishing and painting of automoble bodies and fenders, the prime requisite of a satisfactory and acceptable job is that the surface to be painted should be absolutely smooth. If there are any slight hollows or raised arcas on the surface, regardless of how many coats of lacquer or paint are sprayed on the surface, the imperfections will not be obliterated. It is the usual practice in repainting a body to first level off the body surface by over-filling any arcas of the body that may have been denuded of paint with an undercoating material and then smoothng down these filled arcas to the level of the surrounding original paint. This last step requires the use of a sanding block surfaced with a suitable abrasive paper, the most common of these blocks being constructed of rubber. In Figure 4, I have shown a section 6 of an automobile body covered by an original paint layer l and with two adjoining raised filler coats 8 which occupy areas of the body from which the original paint had view of the sandbeen removed or which may be additional paint coatings applied to the body such as advertising lettering. It will be seen that when a rubber sanding block is passed across the painted surface, the abrasive paper will be forced, by fiexing of the block under pressure of the workmans hand, down into the depressions between the filler coats 8 thus abrading the original paint l, Which should not be touched bythe abrasive paper until the surface to be painted is almost completely smooth and level, and also feather-edging the edges of the filler coats 8 leaving the center portions of the latter considerably elevated above the level of the original paint l. This produces a wavy surface and, when once waved, the surface may not be levelled regardless of how long the sanding is continued, all because the flexible rubber sanding block will follow the hills and hollows and will not cut down the high spots. If a surface prepared in this manner is spray painted the resulting high gloss finish will accentuate the uneveness of the surface by reflecting the highlights and shadows of the hills and hollows. I have provided an improved sanding block which overcomes these difficulties.

In detail, the block comprises a unit piece of sheet metal formed to provide a flat base l2 having relatively narrow upwardly rising fianges l3 at each end thereof and taller fianges M rising vertically from the sides thereof. The adjoining vertical edges of the side and end fianges are suitably joined together by welding or brazing or the entire base including the fianges may be stamp-drawn from a single piece of material. The upper edge l6 of each side flange M is arouately curved and a curved plate l1 is welded, or otherwise secured along its side edges, to the side fianges. This plate has its opposite ends terminating short of the end fianges l3 to form a pair of rectangular openings 18 at the respective ends of the sanding block. When a sheet of abrasive paper is placed on the outer surface of the base l 2 the extending ends of the paper may be folded upwardly over the end fianges l3 and stuffed into the openings l8 so as to attach the paper to the sanding block. The extending side portions of the paper are folded against the sides of the fianges 4, the latter being provided with finger recesses l9 into which the paper may be pressed by the fingers of the operator so as to simultaneously provide for holding the paper on the block and toact as a hand grip.

The bottom surface of the base l2 is provided with a coating of babbitt or other semi-soft metal 2|. This coating of metal, softer than that from which the body of the sanding block is con- .protruding surfaces of the structed, provides a more desirable hacking for the abrasive paper and also, in the event that it becomes nicked and raised in arcas due to accident or rough handling, may, by a few strokes over a piece of abrasive paper layed on a flat surface, be quickly restored to its original flat condition.

As shown in Figure 4, when the sanding operation is performed with the sanding block of my invention, the abrasive paper 22 is held absolutely flat because of the inflexibility of the block thus enabling the operator to quickly level oi the filler coatings 8 and to render the surface to be painted free of hills and hollows. Since it is possible, With the sanding block of my invention to more rapidly and satisfactorily level off the surfacesto be painted, the time required for preparing the surfaces, over that required when the rubber sanding block is used, is considerably lessened thereby resulting in a material speeding up of production, greater profit per job, and a greater assurance, since the work is more perfect, of the customer being entirely satisfied with the paint job.

In Figure I have shown a modified form of sanding block comprising a hollow sheet metal body 23, shaped similarly to the block previously described, to all outer surfaces of which is banded a relatively thin layer of semi-hard rubber 24.

This rubber layer, backed by the sheet metal body 23, will not flex as does the conventional softer rubber block 9, protects the block against denting should it be accidently dropped, and frictionally grips the abrasive paper so that the latter is not likely to wrinkle or roll up during the progress of a sanding operation,

,Having thus described my invention, what I claim as new and desire to secure by Letters Patentis: v

A sanding block to which a sheet of abrasivocoated sheet material may be attached comprising aflat sheet metal base having integral side and end fianges rising from the edges thereof, said side fianges being comparatively longer than said end fianges and being each provided with an arcuate upper edge, an arcuately curved plate Secured along opposite edges to the curved upper edges of said side flanges, said plate terminating at its ends in spaced relation to said end flanges to provide between each end of the plate and an end fiange an opening into Which eXtend-.

ing ends of said sheet material placed against said base may be stuffed so as to secure said sheet material to said base, said base having thereon a layer of metal soiter than the metal from which said base is constructed, and said side flanges each having therein a depressed portion to provide a finger grip.

CARL W. REICHEL. 

